6·H2O, the Equivalent of Görgeyite, a Rare Evaporite Mineral

KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE 267 American Mineralogist, Volume 89, pages 266–272, 2004

Synthesis and characterization of K2Ca5(SO4)6·H2O, the equivalent of görgeyite, a rare evaporite mineral

J. THEO KLOPROGGE,1,* LIESEL HICKEY,1 LOC V. DUONG,2 WAYDE N. MARTENS,1 AND RAY L. FROST1

1Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, 2 George Street, G.P.O. Box 2434, Brisbane, Qld 4001, Australia 2Analytical Electron Microscopy Facility, Faculty of Science, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Qld 4001, Australia

ABSTRACT

Görgeyite, K2Ca5(SO4)6·H2O, is a very rare monoclinic double salt found in evaporites related to the slightly more common mineral syngenite. At 1 atmosphere with increasing external temperature from

25 to 150 °C, the following succession of minerals was formed: first gypsum and K2O, followed at 100 °C by görgeyite. Changes in concentration at 150 °C due to evaporation resulted in the formation of syngenite and finally arcanite. Under hydrothermal conditions, the succession is syngenite at 50 °C, followed by görgyeite at 100 and 150 °C. Increasing the synthesis time at 100 °C and 1 atmosphere showed that initially gypsum was formed, later being replaced by görgeyite. Finally görgeyite was replaced by syngenite, indicating that görgeyite is a metastable phase under these conditions. Under hydrothermal conditions, syngenite plus a small amount of gypsum was formed, after two days being replaced by görgeyite. No further changes were observed with increasing time. Pure görgeyite showed elongated crystals approximately 500 to 1000 μm in length. The infrared and Raman spectra are mainly showing the vibrational modes of the sulfate groups and the crystal water (structural water). Water is characterized by OH-stretching modes at 3526 and 3577 cm–1, OH-bending modes at 1615 and 1647 –1 –1 cm , and an OH-libration mode at 876 cm . The sulfate ν1 mode is weak in the infrared but showed –1 strong bands at 1005 and 1013 cm in the Raman spectrum. The ν2 mode also showed strong bands –1 in the Raman spectrum at 433, 440, 457, and 480 cm . The ν 3 mode is characterized by a complex set –1 –1 of bands in both infrared and Raman spectra around 1150 cm , whereas ν 4 is found at 650 cm .

INTRODUCTION the lower-middle Triassic polyhalite rocks in Nongle, Sichuan Görgeyite is a very rare sulfate double salt closely related to Province, China. Cavaretta et al. (1982, 1983) were the first to report syngen- syngenite, K2Ca(SO4)2.H2O. Although a large number of sulfate salt minerals have been found over the years associated with ite and görgeyite from a geothermal field at Cesano, north of especially evaporite deposits, görgeyite has so far only been Rome, Italy, characterized by brines enriched in Ca, Na, K, Sr, found in a small number of locations. It was first described by Rb, and Li as cations, and SO4 and Cl as anions. They observed Mayrhofer (1953) from the Ischler salt deposit (Leopold-Ho- the görgeyite in a vein consisting of cesanite in association with rizon), Salzburg, Austria. In the same year, a similar mineral, pyrite. The crystals were weakly zoned with Sr content increasing mikheevite, was discovered at Lake Inder, Kazakstan, by Nefe- from core to rim. They also indicated that a small amount of Na dov and reported by Mokievsky (1953). Fleischer (1955) later substituted in the crystal lattice for the divalent cations to reach indicated that both minerals were probably identical. Further stoichiometric balance. data reported by Nefedov (1955) were used by Meixner (1955) As the chemical component potassiumpentacalcium sulfate, to confirm that the minerals were indeed identical. Smith and pentacalcium sulfate, or simply pentasalt, görgeyite has been coworkers reported a third occurrence of görgeyite at Astakós in known for a much longer period of time. Already in the early Western Greece in a Triassic evaporite sequence (Smith and Walls nineteen hundreds, van ʻt Hoff and Geiger synthesized görgeyite 1980; Smith et al. 1964). Seyfarth (1966) reported görgeyite as in the system K2SO4-CaSO4-H2O at temperatures above 32 °C microscopic crystals in Zechstein salt deposits at Staßfurt, south- in experiments aimed at understanding the formation conditions ern Harz, Germany. A year later, Hahne (1967) added another of marine evaporites (van ʻt Hoff 1912; van ʻt Hoff and Geiger three locations in the same area, followed by another three in 1904; van ʻt Hoff et al. 1905). More specific details were later 1988 by Mötzing (1988). The only occurrence outside Europe reported by Krüll and Vetter (1933) and by Hill (1934). Precipi- was reported by Cai et al. (1985), who described görgeyite from tation and crystallization has been shown to take place mainly from saturated solutions. The stability field of görgeyite is very small and is located

* E-mail: [email protected] close to the K2O corner in the Jänecke-triangle, which represents

0003-004X/04/0203–266$05.00 266 KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE 267

the stability field of various minerals with the oxides like K2O on 1b, the opposite was the case. After precipitation the samples were split in half and the corners, surrounded by the fields of syngenite, polyhalite, and either aged in the original solution for three days or hydrothermally treated in an autoclave under autogeneous water vapor pressure, which is the equilibrium water anhydrite. With increasing temperature, the görgeyite stability vapor pressure corresponding to that temperature (samples denoted with extension field shows a small increase (GHACA 1942). Mötzing (1988) –HT). In series 2, the influence of temperature was investigated either at 1 atm identified from thin sections that the görgeyite, from Volkenrode- (~100 kPa) in an oil bath or under hydrothermal conditions (at autogeneous water Poethen (South Harz, Germany) is formed due to metasomatic vapor pressure: 50 °C 12.34 kPa, 100 °C 101.32 kPa, and 150 °C 475.72 kPa) in alteration by descending fluids of extreme compositions. Sylvite an autoclave. Series 3 focused on the kinetics of the formation of syngenite at 100 °C either at 1 atm (~100 kPa) or under hydrothermal conditions (at autogeneous and glaserite were found to be altered to görgeyite, which then water vapor pressure, 101.32 kPa) with increasing from 1 day to 7 days. An over- could react to syngenite. In contrast to this reaction series, Triolo view is given in Table 1. After the treatments, each sample was separated from et al. (1988) reported the recrystallization of syngenite to görgey- the solution by vacuum filtration, followed by intensive washing with deionized ite and arcanite at 225 °C according to the following reaction: water, and dried at 60 °C for 1 hour. X-ray diffraction 5 syngenite → 1 görgeyite + 4 arcanite + 4 water The crystalline materials were characterized by powder X-ray diffraction or (XRD), at Queensland University of Technology. The XRD analyses were carried 5 K2Ca(SO4)2·H2O → K2Ca5(SO4)6·H2O + 4 K2SO4 + 4 H2O out on a Philips wide-angle PW 1050/25 vertical goniometer (Bragg Brentano geometry) applying CoKα radiation (λ = 1.7902 Å, 40 kV, 40 mA). The samples In this paper, the synthesis of görgeyite will be described as were measured at 50% relative humidity in step-scan mode with steps of 0.02 °2θ θ a function of both temperature and pressure, as well as of time and a scan speed of 1.00° per min from 2 to 75 °2 . at constant temperature and pressure, followed by a detailed Scanning electron microscopy characterization using a variety of techniques including X-ray Scanning electron microscope (SEM) photos were obtained on an FEI QUAN- diffraction (XRD), infrared and Raman spectroscopy, scanning TA 200 Environmental Scanning Electron Microscope operating in this case at electron microscopy, and electron microprobe analysis. Up till high vacuum and 15 kV, at Queensland University of Technology. This system is now, characterization was basically based on XRD, chemical equipped with an energy dispersive X-ray spectrometer with a thin window capable analysis, and optical microscopy (Cai et al. 1985; Cavarretta of analyzing all elements of the periodic table down to carbon. A counting time of 100 seconds was applied for the analyses. Due to the presence of a carbon coating, et al. 1983; Mayrhofer 1953; Mötzing 1988). The vibrational necessary for the removal of the electrons from the electron beam from the sample spectroscopy has been hardly described. Only two papers have surface to prevent charging on the görgeyite, no quantitative analyses could be reported an infrared spectrum, but the description and assignment obtained of the impurities on the surface of the görgeyite crystals. of the bands is only very limited (Cai et al. 1985; Cavarretta et al. 1983). Infrared spectroscopy The samples (1 mg) were finely mixed with oven-dried spectroscopic grade CRYSTAL STRUCTURE OF GÖRGEYITE KBr (250 mg) and pressed into a disc under vacuum. The infrared absorption (IR) spectrum of each sample was recorded in triplicate by accumulating 64 scans at The crystal structure has been described in a number of papers 4 cm–1 resolution between 400 cm–1 and 4000 cm–1 using the Perkin-Elmer 1600 (Braitsch 1965; Cavarretta et al. 1983; Mukhtarova et al. 1980, series Fourier transform infrared spectrometer equipped with a LITA detector at 1981; Smith and Walls 1980). Görgeyite is monoclinic and con- Queensland University of Technology. tains four formula units in a cell of dimensions a = 17.51 Å, b Raman microscopy = 6.82 Å, c = 18.21 Å, and β = 113.3° (Smith and Walls 1980). These dimensions are very close to the original dimensions The samples were placed on a polished metal surface on the stage of an Olym- pus BHSM microscope, which is equipped with 10×, 20×, and 50× objectives. The reported by Braitsch (1965), Mukhtarova et al. (1980, 1981) microscope is part of a Renishaw 1000 Raman microscope system, which also (although they reported a monoclinic cell in which the b- and c- includes a monochromator, a filter system and a two-dimensional CCD detec- axes have been inverted), and Cavaretta et al. (1983). The space tor (1024 × 1024 pixels). The Raman spectra were excited by a Spectra-Physics group has been reported as C2/c (no. 15). In the structure, three model 127 He-Ne laser producing highly polarized light at 633 nm and collected –1 ± –1 different Ca atoms can be recognized. Two of them are in ninefold at a resolution of 2 cm and a precision of 1 cm in the range between 200 and 4000 cm–1. Repeated measurements were made on the crystals using the highest coordination by O atoms with average Ca-O distances of 2.52 Å. magnification (50×) to improve the signal to noise ratio in the spectra. Spectra The third Ca atom is in eightfold coordination with an average were calibrated using the 520.5 cm–1 line of a silicon wafer. Ca-O distance of 2.46 Å. The K atom is also in eightfold coordination. The three sulfate anions are approximately regular with Spectral manipulations mean S-O distances of 1.472, 1.477, and 1.470 Å respectively, Baseline adjustment, smoothing, and normalization were performed using but their behavior in providing O atom coordination is different the Spectracalc software package GRAMS (Galactic Industries Corporation, NH, U.S.A.). Band component analysis was carried out using the “Peakfit” for each. The water molecules are situated in voids around the software package by Jandel Scientific. Lorentz-Gauss cross-product functions twofold axes. Although the positions of the hydrogen atoms have were used throughout and peakfitting was carried out until values of 2r > 0.995 not been determined, it is highly likely that hydrogen bonds are were obtained. present in the structure of görgeyite. RESULTS AND DISCUSSION EXPERIMENTAL METHODS Effect of temperature, pressure and time on the synthesis Synthesis of görgeyite Two stock solutions were prepared containing the proper amounts of K2SO4 and

CaSO4 to obtain the stoichiometric ratio necessary for the synthesis of görgeyite. In Figure 1a shows the effect of increasing the external tempera- series 1a, the K2SO4 solution was added to the CaSO4 solution, whereas in series ture up to 150 °C at 1 atm. Figure 1b shows the same experiment 268 KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE 269

TABLE 1. Experimental results of the synthesis of görgeyite as function of pressure and temperature Sample Starting solutions Treatment Time Crystalline products Figure

1a K2SO4 + CaSO4 Water 25 °C 3 days Gp + K2O Not shown 1b CaSO4 + K2SO4 Water 25 °C 3 days Gp + K2O Not shown 1a-HT K2SO4 + CaSO4 Hydrothermal 3 days Anh + K2O Not shown 1b-HT CaSO4 + K2SO4 Hydrothermal 3 days Anh + K2O Not shown 2a K2SO4 + CaSO4 Oil bath 50 °C 7 days Gp + Cc 1a 2b K2SO4 + CaSO4 Oil bath 100 °C 7 days Syn 1a 2c K2SO4 + CaSO4 Oil bath 150 °C 1 day Gör 1a 2d K2SO4 + CaSO4 Oil bath 150 °C 7 days Syn + Gör + trace Gp 1a 2a-HT K2SO4 + CaSO4 Hydrothermal 50 °C 7 days Syn + Gp 1b 2b-HT K2SO4 + CaSO4 Hydrothermal 100 °C 7 days Gör 1b,c 2c-HT K2SO4 + CaSO4 Hydrothermal 150 °C 7 days Anh + trace Gör 1b 3a K2SO4 + CaSO4 Oil bath 100 °C 1 day Gp + trace Gör Not shown 3b K2SO4 + CaSO4 Oil bath 100 °C 2 days Gp + Görg Not shown 3c K2SO4 + CaSO4 Oil bath 100 °C 3 days Gör + trace Gp Not shown 3d K2SO4 + CaSO4 Oil bath 100 °C 4 days Syn + trace Gör Not shown 3f K2SO4 + CaSO4 Oil bath 100 °C 6 days Gör + Syn + Arc Not shown 3a-HT K2SO4 + CaSO4 Hydrothermal 100 °C 1 day Syn + trace Gp 1b,c 3b-HT K2SO4 + CaSO4 Hydrothermal 100 °C 2 days Gör + trace Syn 1c 3c-HT K2SO4 + CaSO4 Hydrothermal 100 °C 3 days Gör + trace Syn 1c 3d-HT K2SO4 + CaSO4 Hydrothermal 100 °C 4 days Gör + trace Syn 1c 3e-HT K2SO4 + CaSO4 Hydrothermal 100 °C 5 days Gör + trace Syn Not shown 3f-HT K2SO4 + CaSO4 Hydrothermal 100 °C 6 days Gör 1c Notes: Gp = gypsum, Anh = anhydrite, Cc = calcite, Syn = syngenite, Gör = görgyeite. but at autogeneous water vapor pressure. All results, also the ones that under these increased pressure conditions, görgeyite seems not shown in the figures, are summarized in Table 1. At 1 atm and to be the stable phase instead of syngenite.

25 °C (samples 1a and 1b), gypsum (CaSO4⋅2H2O), and potash Characterization of görgeyite (K2O) are formed as crystalline products. When the temperature is increased to 100 °C (sample 2b) syngenite is formed (Fig. 1a). Figure 2 shows the XRD pattern of the purest görgeyite Further increases in temperature results in the replacement of sample obtained (2b-HT, hydrothermally treated at 100 °C for syngenite (K2Ca(SO4)2·H2O), by görgeyite (sample 2c). After 7 days), which was also used for the SEM and spectroscopic increasing the synthesis time, syngenite appears again as a reac- investigation. The pattern is in good agreement with data on PDF – tion product next to görgeyite (sample 2d) 18-997 (ICDD-PDF) except for the absence of the 202 reflection Under hydrothermal conditions (increased water vapor pres- in our pattern. The reflections are sharp and intense indicating that sure), the reaction series is significantly different (Fig. 1b). At the crystals are well developed and with a reasonable size. 50 °C, syngenite is already formed (sample 2a-HT). Increasing SEM confirms the XRD observations showing mostly elon- the temperature results in the formation of görgeyite at 100 °C gated, almost needle-like crystals approximately 500 to 1000 μm (sample 2b-HT), whereas at higher temperatures and autogeneous in length. Although the crystals are not developed completely, water vapor pressures, anhydrite (CaSO4), is formed as the only regularly some of the crystal faces can be recognized (Fig. 3a). crystalline component (sample 2c-HT). These results are more in EDS analysis confirms the composition of görgeyite (Fig. 3b). agreement with the recrystallization reaction reported by Triolo On the surface of most crystals, small secondary equidimensional et al. (1988), although at temperatures much lower than the 225 particles and very small needles are visible (Figs. 3c and 3d). All °C used in their experiments. the XRD patterns showed a very minor calcite impurity, possibly

The second series of experiments involved time studies at 100 formed from dissolved CO2 from the atmosphere reacting with °C in order to evaluate the kinetics involved and the stability of Ca cations in solution. Upon further enlargement of the small the minerals formed (Fig. 1c). At 1 atm, increasing the duration equidimensional particles, the characteristic crystal morphol- of the experiment from 1 to 3 days resulted in a decrease in the ogy of calcite becomes evident. EDS analysis confirmed that amount of gypsum, while syngenite was being replaced by gör- these particles are indeed calcite, while the needles have the geyite (samples 3a to 3c). Further increasing the time resulted in composition of gypsum. The amount of gypsum, however, is so the formation of syngenite replacing görgeyite (samples 3d and small that it could not be identified in the XRD patterns (Figs. 3f). This result indicates that, under these temperature conditions 3e and 3f). at 1 atm, syngenite rather than görgeyite is the thermodynami- Thus far, two papers have published infrared spectra of natu- cally stable phase. Thus, görgeyite is formed metastably. ral görgeyite. The spectrum of evaporitic görgeyite from China As with the temperature experiments, the results under au- reported by Cai et al. (1985) closely resembles the spectrum togenous water vapor pressures is significantly different. After 1 obtained from the synthetic görgeyite in this study. In contrast, day, syngenite is formed together with a small amount of gypsum. the spectrum of the geothermal görgeyite reported by Cavaretta Here the increase in time results in the disappearance of the et al. (1983) shows major differences. Even though they reported syngenite and replacement by görgeyite after 2 days (samples a low-resolution spectrum, it is clear that the crystal water OH- 3a-Ht and 3b-HT). Further increasing the time results in dimin- stretching modes are shifted by more than 50 cm–1 toward lower ishing amounts of syngenite (up to 6 days), while after 7 days wavenumbers. The same is true for the corresponding water OH- only görgeyite is formed (samples 3b-HT to 3f-HT), indicating bending mode around 1600 cm–1, although to a lesser degree. 268 KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE 269

a c � � �

� ��

��

� ��

�� FIGURE 1. Powder XRD patterns of the products formed: (a) 7 days b atKloprogge 1 atm et al.with increasing temperature, (b) 7 days under hydrothermalFig. 1b conditions with increasing temperature, and (c) with increasing time at Kloprogge et al. �� Fig. 1a a constant temperature of 100 °C at 1 atmosphere. Abbreviations used �� in the figure are listed in Table 1.

�� FIGURE 2. Powder XRD pattern of görgeyite containing a minor Kloproggeamount et al. of calcite impurity. Fig. 2

Furthermore, the bands between 1980 and 2380 cm–1 were as- �� signed to OH in the görgeyite structure. This assignment seems �� very unlikely and the bands are probably due to hydrocarbon impurities in their system. No details are visible in the ν1 and ν3 region between 1000 and 1200 cm–1. Cavaretta et al. (1983) gives � �� no indication about sample preparation, but the fact that a trans- �� mission spectrum is shown suggest that a powdered sample was

Kloprogge et al. Fig. 1c 270 KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE 271 a b

FIGURE 3. (a) Scanning electron microscopy image of görgeyite 2b-HT, (b) corresponding EDS pattern, (c) enlargement of the görgeyite surface showing equidimensional calcite and needles of gypsum, (d) enlargement of a group of calcite crystals, (e) EDS pattern of gypsum and (f) EDS pattern of calcite. Both the EDS patterns of gypsum and calcite show a background signal of the görgeyite. 270 KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE 271

used. Due to the fact that the görgeyite was retrieved from core 3377, and 3510 cm–1 (Kloprogge et al. 2002). The corresponding –1 samples where it is associated with cesanite [Na3Ca2(SO4)3(OH)] OH-bending modes are observed at 1615 and 1647 cm in the and pyrite leaves open the possibility that the sample used for infrared spectrum. The corresponding libration mode is present the infrared analysis was not completely pure. The presence of in the infrared spectrum at 876 cm–1. cesanite and/or hydrocarbons would explain the shift in OH- Theoretically (Ross 1974), when the sulfate retains its full

modes and the loss of details in the sulfate modes. symmetry (Td), four modes of vibration will be observed: ν1(A1) –1 –1 –1 Figure 4 shows the infrared absorption and the Raman at 983 cm , ν2(E) at 450 cm , ν3 at 1105 cm , and ν4(F2) at –1 spectra of görgeyite 2b-HT (bottom and middle spectra). For 611 cm . The A1 (symmetric stretching) and E (bending) modes

comparative purposes, the infrared spectrum of syngenite is also are Raman active only, whereas the F2 stretching and bending included in the figure (top spectrum). The spectra consist of modes are both Raman and infrared active. Ross (1974) reported

vibrational modes associated with crystal water, sulfate groups, a site symmetry of Cs or C1 for the sulfate group in syngenite.

or the lattice modes. The crystal structure of görgeyite indicates In görgeyite, the sulfate group is also present at C1 sites. This

the presence of one type of water present at a C1 point-group site symmetry C1 will lead to either 6 A' + 3 A'' or 9 A, therefore site, whereas three different sulfate groups are present in the nine Raman and nine infrared active modes for each sulfate

structure; all of them are also present at C1 point-group sites. group. As a result, the Raman and infrared spectra of görgeyite The observation in the OH-stretching region between 2900 and are very complex in the region below 1400 cm–1. Table 2 gives –1 4000 cm confirms the C1 point-group site for water, with two an overview of all the peak positions.

distinct bands visible in the infrared spectrum at 3526 and 3577 The ν 1 sulfate mode is weak in the infrared but very strong cm–1 together with, compared to the infrared spectrum, two weak and sharp in the Raman spectrum with two strong bands at 1005 –1 –1 bands at slightly different wavenumbers at 3525 and 3579 cm and 1013 cm . Similarly, the ν2 mode is very weak in the infrared in the Raman spectrum. The spectrum is clearly different from spectrum but strong in the Raman spectrum, with four clearly –1 that of syngenite, which is characterized by a very broad band visible bands around 433, 440, 457, and 480 cm . The ν3 is consisting of various overlapping OH-stretching modes at 3248, characterized by a complex set of bands around 1150 cm–1 in both the infrared and Raman spectra. Here, the bands are distinctly stronger in the infrared than in the Raman spectrum. The same –1 holds true for the ν4 mode around 650 cm .

Syngenite Rel. Raman Intensity TABLE 2. Infrared and Raman band positions for görgeyite in comparison to syngenite (Kloprogge et al. 2002) IR görgeyite (cm–1) Raman görgeyite IR syngenite Assignment (cm–1) (cm–1) 281 lattice

418 433 ν2 SO4

Rel. IR Abs. Intensity Abs. IR Rel. 440 440 439 457 457 Görgeyite 474 480 491

595 595 596 ν4 SO4 400 600 800 1000 1200 1400 1600 1800 612 602 604 Wavenumber/cm-1 628 631 617 653 654 657 670 661 Kloprogge et al. 712 711 876 754 Water OH-libration

980 ν1 SO4 997 999 Rel. Raman Intensity Syngenite 1006 1005 1013 1072 1067 1078 1084 1085

1105 1108 1110 ν3 SO4

Rel. IR Abs. Intensity Abs. IR Rel. 1117 1115 1125 1141 1137 1136 Görgeyite 1158 1161 1148 1164 1175 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 1188 1187 1193 Wavenumber/cm-1 1232 1215 1615 Water OH-bending 1647 1631 Kloprogge et al. 3248 Water OH-stretching FIGURE 4. Infrared and Raman spectra of görgeyite 2b-HT in 3377 comparison to the infrared spectrum of syngenite in the range between 3526 3525 3510 (a) 400 and 1900 cm–1 and (b) 2900 and 3900 cm–1. 3579 3579 272 KLOPROGGE ET AL.: SYNTHESIS AND CHARACTERISATION OF GÖRGEYITE

ACKNOWLEDGMENTS 82, 311–317. Mötzing, R. (1988) Goergyeit im Zechstein 2. Chemie der Erde, 48, 233–244. The financial support and infrastructure of the Queensland University of Tech- Mukhtarova, N.N., Kalinin, V.R., Rastsvetaeva, R.K., Ilyukhin, V.V., and Belov, nology, School of Physical and Chemical Sciences and the Inorganic Materials N.V. (1980) Crystal structure of gorgeyite K2Ca5(SO4)6⋅H2O. Soviet Physics, Research Program is gratefully acknowledged. Doklady, 25, 323–325. Mukhtarova, N.N., Rastvetaeva, R.K., Ilyukhin, V.V., and Belov, N.V. (1981) Crys- REFERENCES CITED tal chemistry of sulfates. Structural features of gorgeyite. Mineralogicheskii Zhurnal, 3, 24–35. Braitsch, O. (1965) Zur Gittermetrik des Gorgeyit K2Ca5(SO4)6⋅H2O. Neues Jahr- buch fuer Mineralogie, Monatshefte, 4, 126–8. Nefedov, E.I. (1955) Neue Minerale. Geologie, 5, 526–528. Cai, K., Zhao, D., Liao, L., and Huang, X. (1985) The mineralogy of gorgeyite. Ross, S.D. (1974) Sulphates and other oxy-anions of group VI. In V.C. Farmer, Earth Science. Journal of China University of Geoscience, 10, 21–28. Ed., The Infrared Spectra of Minerals, p. 423–444. Mineralogical Society Cavarretta, G., Mottana, A., and Tecce, F. (1982) Goergeyite e syngenite nei pozzi England. geotermici di Cesano (Lazio). In Atti del Congresso della Societa Italiana di Seyfarth, H.-H. (1966) Umbildungserscheinungen in Salzgesteinen der Stassfurtse- Mineralogia e Petrologia, 38, p. 902. Pavia, Italy. rie. Universität Jena, Jena. ——— (1983) Görgeyite and syngenite in the Cesano geothermal field (Latium, Smith, G.W. and Walls, R. (1980) The crystal structure of görgeyite K2SO4.5 ⋅ Italy). Neues Jahrbuch fuer Mineralogie, Abhandlungen, 147, 304–314. CaSO4 H2O. Zeitschrift fuer Kristallographie, 151, 49–60. Fleischer, M. (1955) New mineral names. American Mineralogist, 40, 551. Smith, G.W., Walls, R., and Whyman, P.I. (1964) An occurrence of görgeyite in GHACA (1942) Kalium. Gmelins Handbuch der anorganischen Chemie, Anhang- Greece. Nature, 203, 1061–1062. band. Verlag Chemie GmbH, Weinheim/Bergstr. und Berlin. Triolo, I., Mottana, A., and Giampaolo, C. (1988) Synthesis and thermal behaviour Hahne, B. (1967) Sulfat mineralien im Bereich der Sudharzgruben Volkenroda und of syngenite. Terra Cognita, 8, 79. Pöthen (Kaliwerk Volkenroda). Universität Jena, Jena. van ʻt Hoff, J.H. (1912) Untersuchungen über die Bildungsverhältnisse der Hill, A.E. (1934) Ternary systems XIX, calcium sulfate, potassium sulfate and ozeanischen Salzablagerungen insbesondere des Stassfurter Salzlagers, p. water. Journal of the American Chemical Society, 56, 1071–1078. 275–277. Akademische Verlagsgesellschaft, Leipzig. Kloprogge, J.T., Schuiling, R.D., Ding, Z., Hickey, L., Wharton, D., and Frost, van ʻt Hoff, J.H. and Geiger, A. (1904) Untersuchungen über die Bildungsverhät- R.L. (2002) Vibrational spectroscopic study of syngenite formed during the nisse der ozeanischen Salzablagerungen. XXXVII. Kaliumpentakalziumsulfat treatment of liquid manure with sulphuric acid. Vibrational Spectroscopy, und eine dem Kaliborit verwandte Doppelverbindung, p. XXVIII, 935–937. 28, 209–221. Preussischen Akademie der Wissenschaften zu Berlin. Krull, F. and Vetter, O. (1933) Die kristallographischen und kristallopischen van ʻt Hoff, J.H., Voermann, G.L., and Blasdale, W.C. (1905) Untersuchungen über Eigenschaften des Kaliumpentacalciumsulfats und seine Dichte. Zeitschrift die Bildungsverhätnisse der ozeanischen Salzablagerungen. XLI. Die Bildung- fuer Kristallographie, 86, 389–394. stemperatur des kaliumpentacalciumsulfats., p. XII, 305–310. Sitzungsberichte Mayrhofer, H. (1953) Gorgeyit, ein neues Mineral aus der Ischler Salzlagerstatte. der Königlichen Preussischen Akademie der Wissenschaften zu Berlin. Neues Jahrbuch fuer Mineralogie, Monatshefte, 35–44. Meixner, H. (1955) Zur Identität von Mikheewit (Micheewit) mit Görgeyit. Ge- ologie, Berlin, 6, 576–578. MANUSCRIPT RECEIVED DECEMBER 1, 2002 Mokievsky, V.A. (1953) The scientific session of the Fedorov Institute together MANUSCRIPT ACCEPTED AUGUST 19, 2003 with the All-Union mineralogical Society. Zapiski Vses Mineral Obshchestva, MANUSCRIPT HANDLED BY MICHAEL FECHTELKORD